Merge pull request #446 from dlambda/co-br

checkout-branch example

3 files changed, 124 insertions, 35 deletions

diff --git a/Makefile b/Makefile
index 1e10396..3d5b54f 100644
--- a/Makefile
+++ b/Makefile
@@ -28,6 +28,7 @@ build-git:
 test:
 	@echo "running against `git version`"; \
 	$(GOTEST) -race ./...
+	$(GOTEST) -v _examples/common_test.go _examples/common.go --examples
 
 TEMP_REPO := $(shell mktemp)
 test-sha256:
diff --git a/_examples/checkout-branch/main.go b/_examples/checkout-branch/main.go
new file mode 100644
index 0000000..59dfdfc
--- /dev/null
+++ b/_examples/checkout-branch/main.go
@@ -0,0 +1,85 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/go-git/go-git/v5"
+	. "github.com/go-git/go-git/v5/_examples"
+	"github.com/go-git/go-git/v5/config"
+	"github.com/go-git/go-git/v5/plumbing"
+)
+
+// Checkout a branch
+func main() {
+	CheckArgs("<url>", "<directory>", "<branch>")
+	url, directory, branch := os.Args[1], os.Args[2], os.Args[3]
+
+	// Clone the given repository to the given directory
+	Info("git clone %s %s", url, directory)
+	r, err := git.PlainClone(directory, false, &git.CloneOptions{
+		URL: url,
+	})
+	CheckIfError(err)
+
+	// ... retrieving the commit being pointed by HEAD
+	Info("git show-ref --head HEAD")
+	ref, err := r.Head()
+	CheckIfError(err)
+
+	fmt.Println(ref.Hash())
+
+	w, err := r.Worktree()
+	CheckIfError(err)
+
+	// ... checking out branch
+	Info("git checkout %s", branch)
+
+	branchRefName := plumbing.NewBranchReferenceName(branch)
+	branchCoOpts := git.CheckoutOptions{
+		Branch: plumbing.ReferenceName(branchRefName),
+		Force:  true,
+	}
+	if err := w.Checkout(&branchCoOpts); err != nil {
+		Warning("local checkout of branch '%s' failed, will attempt to fetch remote branch of same name.", branch)
+		Warning("like `git checkout <branch>` defaulting to `git checkout -b <branch> --track <remote>/<branch>`")
+
+		mirrorRemoteBranchRefSpec := fmt.Sprintf("refs/heads/%s:refs/heads/%s", branch, branch)
+		err = fetchOrigin(r, mirrorRemoteBranchRefSpec)
+		CheckIfError(err)
+
+		err = w.Checkout(&branchCoOpts)
+		CheckIfError(err)
+	}
+	CheckIfError(err)
+
+	Info("checked out branch: %s", branch)
+
+	// ... retrieving the commit being pointed by HEAD (branch now)
+	Info("git show-ref --head HEAD")
+	ref, err = r.Head()
+	CheckIfError(err)
+	fmt.Println(ref.Hash())
+}
+
+func fetchOrigin(repo *git.Repository, refSpecStr string) error {
+	remote, err := repo.Remote("origin")
+	CheckIfError(err)
+
+	var refSpecs []config.RefSpec
+	if refSpecStr != "" {
+		refSpecs = []config.RefSpec{config.RefSpec(refSpecStr)}
+	}
+
+	if err = remote.Fetch(&git.FetchOptions{
+		RefSpecs: refSpecs,
+	}); err != nil {
+		if err == git.NoErrAlreadyUpToDate {
+			fmt.Print("refs already up to date")
+		} else {
+			return fmt.Errorf("fetch origin failed: %v", err)
+		}
+	}
+
+	return nil
+}
diff --git a/_examples/common_test.go b/_examples/common_test.go
index 6630f15..5e3f753 100644
--- a/_examples/common_test.go
+++ b/_examples/common_test.go
@@ -2,10 +2,10 @@ package examples
 
 import (
 	"flag"
-	"go/build"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"testing"
 )
 
@@ -14,26 +14,43 @@ var examplesTest = flag.Bool("examples", false, "run the examples tests")
 var defaultURL = "https://github.com/git-fixtures/basic.git"
 
 var args = map[string][]string{
-	"branch":      {defaultURL, tempFolder()},
-	"checkout":    {defaultURL, tempFolder(), "35e85108805c84807bc66a02d91535e1e24b38b9"},
-	"clone":       {defaultURL, tempFolder()},
-	"context":     {defaultURL, tempFolder()},
-	"commit":      {cloneRepository(defaultURL, tempFolder())},
-	"custom_http": {defaultURL},
-	"open":        {cloneRepository(defaultURL, tempFolder())},
-	"progress":    {defaultURL, tempFolder()},
-	"push":        {setEmptyRemote(cloneRepository(defaultURL, tempFolder()))},
-	"revision":    {cloneRepository(defaultURL, tempFolder()), "master~2^"},
-	"showcase":    {defaultURL, tempFolder()},
-	"tag":         {cloneRepository(defaultURL, tempFolder())},
-	"pull":        {createRepositoryWithRemote(tempFolder(), defaultURL)},
-	"ls":          {cloneRepository(defaultURL, tempFolder()), "HEAD", "vendor"},
-	"merge_base":  {cloneRepository(defaultURL, tempFolder()), "--is-ancestor", "HEAD~3", "HEAD^"},
+	"blame":                      {defaultURL, "CHANGELOG"},
+	"branch":                     {defaultURL, tempFolder()},
+	"checkout":                   {defaultURL, tempFolder(), "35e85108805c84807bc66a02d91535e1e24b38b9"},
+	"checkout-branch":            {defaultURL, tempFolder(), "branch"},
+	"clone":                      {defaultURL, tempFolder()},
+	"commit":                     {cloneRepository(defaultURL, tempFolder())},
+	"context":                    {defaultURL, tempFolder()},
+	"custom_http":                {defaultURL},
+	"find-if-any-tag-point-head": {cloneRepository(defaultURL, tempFolder())},
+	"ls":                         {cloneRepository(defaultURL, tempFolder()), "HEAD", "vendor"},
+	"ls-remote":                  {defaultURL},
+	"merge_base":                 {cloneRepository(defaultURL, tempFolder()), "--is-ancestor", "HEAD~3", "HEAD^"},
+	"open":                       {cloneRepository(defaultURL, tempFolder())},
+	"progress":                   {defaultURL, tempFolder()},
+	"pull":                       {createRepositoryWithRemote(tempFolder(), defaultURL)},
+	"push":                       {setEmptyRemote(cloneRepository(defaultURL, tempFolder()))},
+	"revision":                   {cloneRepository(defaultURL, tempFolder()), "master~2^"},
+	"sha256":                     {tempFolder()},
+	"showcase":                   {defaultURL, tempFolder()},
+	"tag":                        {cloneRepository(defaultURL, tempFolder())},
 }
 
-var ignored = map[string]bool{}
+// tests not working / set-up
+var ignored = map[string]bool{
+	"azure_devops":    true,
+	"ls":              true,
+	"sha256":          true,
+	"submodule":       true,
+	"tag-create-push": true,
+}
+
+var (
+	tempFolders = []string{}
 
-var tempFolders = []string{}
+	_, callingFile, _, _ = runtime.Caller(0)
+	basepath             = filepath.Dir(callingFile)
+)
 
 func TestExamples(t *testing.T) {
 	flag.Parse()
@@ -44,13 +61,13 @@ func TestExamples(t *testing.T) {
 
 	defer deleteTempFolders()
 
-	examples, err := filepath.Glob(examplesFolder())
+	exampleMains, err := filepath.Glob(filepath.Join(basepath, "*", "main.go"))
 	if err != nil {
 		t.Errorf("error finding tests: %s", err)
 	}
 
-	for _, example := range examples {
-		dir := filepath.Dir(example)
+	for _, main := range exampleMains {
+		dir := filepath.Dir(main)
 		_, name := filepath.Split(dir)
 
 		if ignored[name] {
@@ -71,20 +88,6 @@ func tempFolder() string {
 	return path
 }
 
-func packageFolder() string {
-	return filepath.Join(
-		build.Default.GOPATH,
-		"src", "github.com/go-git/go-git/v5",
-	)
-}
-
-func examplesFolder() string {
-	return filepath.Join(
-		packageFolder(),
-		"_examples", "*", "main.go",
-	)
-}
-
 func cloneRepository(url, folder string) string {
 	cmd := exec.Command("git", "clone", url, folder)
 	err := cmd.Run()